Recent years have seen a rapid spread of inkjet printers for their advantages such as high-speed printing, low operating noise, high-resolution printing, and low cost. For an inkjet printer to achieve high-resolution printing, ink needs to be formed into a meniscus shape at the exit of a nozzle and be propelled stably and orthogonally to the printed surface. If the exit surface of the nozzle becomes wet and spread with ink, no stable meniscus shape is obtained, and thus high-resolution printing cannot be achieved. This is generally coped with by providing a liquid-repellent film on the exit surface of the nozzle. For example, in a case where a nozzle is formed on a nozzle plate, which is the tip-end part of an inkjet head, a liquid-repellent film is typically formed on the exit-side surface of the nozzle plate. Various methods have been proposed for formation of such a liquid-repellent film.
For example, according to a method disclosed in Patent Document 1 listed below, liquid-repellent agent is absorbed in sponge, and is then transferred to a nozzle exit surface. On the other hand, according to a method disclosed in Patent Document 2 listed below, a nozzle plate is treated to be liquid-repellent, and is then attached to a dummy substrate; then, nozzle holes are formed by etching.